1. Field of the Invention
The present invention relates to an image display apparatus.
2. Description of the Related Art
Image display apparatuses such as liquid crystal display (LCD), plasma display panel (PDP), organic electroluminescence display (OLED), and field emission display (FED) are known. These image display apparatuses are required to have high luminance. Japanese Patent Application Laid-Open No. 11-283751 discusses a technique purported to improve light extraction efficiency of the OLED by using a diffraction grating or a zone plate.
The inventors of the present invention, however, found that a structure where the diffraction grating is arranged all over the light emitting layer of the OLED, as discussed in Japanese Patent Application Laid-Open No. 11-283751, cannot provide adequate luminance.